1. Field of the Invention
The invention relates to a flow-forming method in which an axially symmetrical workpiece is fixed at a free end of a spinning mandrel having an external profile; the spinning mandrel together with the workpiece are rotated and at least one spinning roll is infed, said workpiece being shaped to the external profile of the spinning mandrel.
The invention also relates to a flow-forming apparatus with a spinning mandrel having an external profile and on which can be fixed a workpiece, a drive by which the spinning mandrel and the workpiece can be rotated together and at least one spinning roll for shaping the workpiece to the external profile of the spinning mandrel.
2. Description of Related Art
Methods and apparatuses of the same species are adequately known. For example, a cup-shaped starting workpiece is mounted on a spinning mandrel with a substantially cylindrical outer contour and the axially extending edge of the workpiece is shaped initially by radial and/or axial infeeding of a spinning roll to the spinning mandrel. External teeth can be provided on the spinning mandrel so that these external teeth are pressed into the cup-shaped workpiece. In the known methods and apparatuses, it is problematical that, as a result of the action of the spinning roller, considerable forces are exerted on the external teeth of the spinning mandrel so that, during the pressing in of the teeth, high bending stresses and repeated stress reversals occur on the individual tool teeth. After a relatively short time, these stresses can lead to tooth breakage and consequently to the destruction of the spinning mandrel.
In the flow-forming, cup-shaped, internally toothed workpiece, the problem exists that, at the free edge of the workpiece, the teeth are frequently not completely shaped. Thus, workpieces are conventionally worked with a certain axial oversize which must subsequently be dressed by machining.
Rechucking and dressing in a further working machine are disadvantageous. It is particularly problematical that, on the dressed edge of the internal teeth, a burr is left behind, which can hardly be removed mechanically, so that frequent manual deburring is required.